Plant Material and Growth Conditions
Seeds of two independent transgenic barley (Hordeum vulgare L. cv. Golden Promise) lines (W1-1 and W1-7) with RNAi knockdown of theWHIRLY1 gene and wild type controls were produced as described previously (Krupinska et al., 2002). Barley seeds (1 per pot) were sown in pots in compost (SHL professional potting compost) in controlled environment chambers with a 16h light/8h dark photoperiod, with an irradiance of 250 μmol m-2s-1, 20ºC/16ºC day/night temperature regime and 60% relative humidity. The primary leaves were harvested after 7 days.